NEW ALBIAN (EARLY CRETACEOUS) OPHIUROIDS FROM THE TLAYÚA QUARRY, PUEBLA, MEXICO

Abstract:  On the basis of six articulated individuals from the middle to late Albian lithographic limestone at Tlayúa near Tepexi de Rodríguez (Puebla, Mexico), a new species of ophiuroid, Ophiactis applegatei , is described. The material adds to the rather poor record of Early Cretaceous brittlestars and represents the oldest known member of the family Ophiactidae, being based on well-preserved and articulated specimens and thus reasonably well defined morphologically. The rarity of ophiuroids, their complete preservation as well as the unnatural contortions of their arms suggest these specimens to be allochthonous, having been transported into a hostile environment where burial was rapid.     

Mercapturic acids as biomarkers of exposure to electrophilic chemicals:applications to environmental and industrial chemicals

The use of mercapturic acids (N-acetyl-L-cysteine S-conjugates, MAs) in the biological monitoring of human exposure to environmental and industrial chemicals is receiving more and more attention. Mercapturic acids (MAs) are formed from glutathione (GSH) S-conjugates via the MA-pathway. Although this pathway can lead to different end-products, the formation of MAs is the predominant route in most species, including man. Two GSH S-transferases (GSTs) show genetic polymorphisms in humans and this can have major consequences for individual susceptibility to toxic effects and for MA formation. In occupational toxicology, adducts to biomacromolecules are also used as biomarkers. DNA adducts are a measure for the effective dose, while protein adducts are related to the dose at critical site. Both type of adducts are normally determined in blood, while MAs are determined in urine. Most MAs are excreted with relatively short half-lifes, allowing a direct evaluation of the occupational circumstances. For many compounds similar (linear) dose-dependency was found for MA excretion, formation of macromolecular adducts, and for various biomarkers of toxic effects. These relations together with fact that MAs relate to the electrophilic character of compounds, allows for the conclusion that MAs are biomarkers of toxicologically relevant internal doses of chemicals or their metabolites. An overview will be given here of the use of MAs in the assessment of internal human exposure to electrophilic environmental and industrial chemicals. Additionally, the formation of GSH S-conjugates, their catabolism to MAs and several of the frequently used analytical approaches are discussed. When appropriate, the influence of genetic polymorphisms on formation of MAs and on susceptibility to toxicity will be discussed for different chemicals as well.     

The evolution of environmentally-cued pupal colour in swallowtail butterflies: natural selection for pupation site and pupal colour

1. Environmentally-cued pupal colour in swallowtail butterflies has been hypothesized to evolve as a consequence of (a) the evolution of a preference for pupation sites above the ground that vary in colour and (b) natural selection for crypsis on such sites.
2. This hypothesis was tested by comparing the field survival of green and brown Papilio polyxenes Fabr. pupae placed on green or brown pupation sites that were either above the ground on near the ground.
3. Green pupae on green sites above the ground had a significantly higher probability of survival than did all other pupal colour and pupation site combinations.
4. Pupae on sites above the ground were more likely to be preyed upon during the day, whereas those on sites near the ground were more likely to be preyed upon during the night, suggesting that variation in nocturnal and diurnal predation influences the evolution of pupation site preference.
5. To the extent that diurnal predators use colour vision to locate prey, diurnal predation should favour environmentally-cued pupal colour.     

Kastom,Christianity and the First Ancestor of the Kwara'ae of Malaita

The Kwara'ae of Malaita, now mainly Christian and enmeshed in the cash economy, invoke an ideology of kastom, reconciling biblical and ancestral origins, validating land claims, and legitimizing as traditional postcolonial political hierarchies built on the old ritual svstem. The political uses of kastom ideology in contemporary Kwara'ae, and their historical roots, are explored.     

The Rift Valley is a major barrier to dispersal of African clawed frogs (Xenopus) in Ethiopia

The Ethiopian highlands – home to striking species diversity and endemism – are bisected by the Rift Valley, a zone of tectonic divergence. Using molecular data we examined the evolutionary history of two co‐distributed species of African clawed frog (Xenopus clivii and X. largeni) that are endemic to this region. Our field collections substantially extend the known distribution of X. largeni, a species formerly known from highlands southeast of the Rift, but that also occurs to the northwest. In both species, analysis of mitochondrial DNA and 19 autosomal loci identifies significant population structure, suggests little or no recent migration across the Rift Valley, and provides divergence time estimates across the Rift of ～1–3.5 million years. These results indicate that the Ethiopian Rift Valley is a major obstacle to dispersal of highland‐adapted amphibians.     

White-Tailed Deer Antler Research: A Response to Demarais and Strickland

ABSTRACT Demarais and Strickland presented several questions about the scope and validity of conclusions regarding predictability of mature antler size based on yearling antler size and produced a simulation model reported to demonstrate measurement bias in our 2008 study. We believe our conclusions were appropriate with our research hypothesis and demonstrated the assumed differential selection bias by hunters used in Demarais and Strickland was unwarranted. Demarais and Strickland provided no metadata to document the provenance of data used in their model and did not account for location, year, cohort, nutrition of research animals, or loss of individuals from their sample population by accidents or death: the same questions raised in their critique. Additionally, selection and experimental design problems in a portion of their sample population indicate their model results are questionable. Our responses to Demarais and Strickland will aid wildlife managers in making future culling decisions in white-tailed deer management.